1. Field of the Invention
The present invention relates to an improved nitrogen laser and, more particularly, to an improved gaseous mixture apparatus for supplying the same for use in nitrogen lasers.
2. Description of Related Art
Nitrogen lasers are known in the prior art, as shown in FIG. 4. Such a laser operates by providing a high voltage pulse between two oppositely disposed electrodes, thereby bringing about a discharge excitation, which can be seen as area A on FIG. 4. Nitrogen gas enters through an inlet port 3 into an excitation chamber 2 containing the two discharge electrodes 1 and 1'. When the electrodes discharge, nitrogen molecules coming into the chamber 2 from inlet port 3 are ionized by the discharge pulse. The nitrogen ions will subsequently recombine to form neutral nitrogen molecules. This recombination can take a significant period of time to occur. Further, the recombination will also occur on the surface of the discharge electrodes and along the inner walls of the chamber 2. Therefore, a large number of nitrogen ions will remain within the discharge chamber and between the electrodes after each discharge pulse. This leads to a lower energy potential between the discharge electrodes, making it difficult for the nitrogen ions to reach sufficient energy levels to become nitrogen molecules. Also, the presence of a large number of nitrogen ions yields a proportionately lower amount of nitrogen molecules. This proportionately lower amount of nitrogen molecules renders the operation or the transmission of the nitrogen laser inherently more difficult. Therefore, using the construction of lasers shown as FIG. 4, the recombination of the nitrogen ions takes a sufficiently long period of time, so as to make impossible the operation of a high repetition laser, such as a 1-kHz repetition rate.
FIG. 5 charts the power output of a nitrogen laser of FIG. 4. As can be seen, the laser has an initial poor stability over a period of time. Furthermore, FIG. 5 shows a decrease in the total mean output of the laser over the period of time. FIG. 5 employs a nitrogen and gas flow rate of 3 liters per minute.
FIG. 6 shows an output of the laser shown in FIG. 4 at a pulse rate of 1 kHz. Thus, the stability during this time period under the stated conditions can be seen as being .+-.25%.
In order to carry out the operation of a high repetition laser, it is necessary to keep the chamber 2 supplied with a fresh supply of nitrogen gas N.sub.2. However, this requirement leads to increased consumption of N.sub.2 gas to such an extent that a dramatic increase in the cost of operating the conventional nitrogen laser is seen. Accordingly, a nitrogen laser capable of operating at a high repetition rate, exceeding 100 Hz, has not been introduced onto the market, and there is a need in the prior art to provide for an improved nitrogen laser that resolves the above problems.